When you copy multiple files in OS X and the destination folder already has files of the same name, you don't have a lot of choice over what to do—you can either cancel the copy, or replace the files. This little trick gives you a bit more power.

It may not be as easy as Windows 8's new copy dialog, but OS X actually has a few hidden options if, say, you want to keep some of the old files and replace other ones. Web site Mac OS X Hints explains:

In Lion, one of the new features is to be able to 'Keep Both Files' when copying multiple files in Finder. While this is useful there are many times when the old 'Skip' behavior is better suited to the task. Well, the (now) obvious way to do this is to just hold the 'Option' key, and then 'Keep Both File' changes to 'Skip.'